Accurate positioning of cut over artwork


#1

I’m hoping someone can help as I am close to giving up and sending my machine back. It seems like what I am trying to do (and what I bought and waited a year for the machine for) should be so easy but I just can’t get it to do what I want.

Originally I tried the scanning option but that was so far off it was ridiculous, so now I am using SVG files. So I have an Inkscape file with two layers. One contains the artwork, the second contains the outlines of the artwork. I print the artwork on paper, glue it to the wood (thick proofgrade walnut plywood). Then I load the outline layer into the glow forge app. First of all the scale of the outlines is nothing like the scale on the artwork (yet they are the same in Inkscape), and there seems no way to accurately cut the outline. Like in the photo it might look like I can get one to seem like it will cut accurately, but it doesn’t. I made two cuts on this one, the second positioning looked wrong but I could adjust it based on the first cut. I want to make many of these from one sheet of wood, so this obviously isn’t going to work. I’ve tried right in the middle under the camera, and even then it is not accurate. Is there any way to do this accurately?


#2

If you are doing two separate operations, then a layered file like you are using is key. Ignore the 2nd pass when cutting the first, then switch it up.

The other key is to make sure your piece does not move between the two passes. If you have to take the piece out or flip it or whatever between the two operations, then cut some kind of a template that holds the piece in the correct position between passes. The holder cut should be in the same document.

I.e.

Pass 1: Cut out the holder piece, oft out of cardboard (ignoring 2 and 3 in the UI)
Pass 2: Insert the thing you want to make into the holder piece and do the first pass (ignoring 1 and 3)
Pass 3: Ignore pass 1 and 2 operations, do pass 3 operations.

The alignment will get better over time. It is a software issue, at this point. It has already improved immensely in the past 6 months.


#3

Yep. Take a piece of paper and draw a cross (or several spread out on the paper). Then load a design that’s just a cross to score. With the paper held down so it doesn’t move, use the lightest power settings that will leave a mark and center the design over the image of the cross on the paper. Score it. Then see how far off you are. Move your design a few clicks in the direction you need to go for it to land where you want (write down how many clicks you did). Score again. Keep doing that until you get it dead on.

Do it again with a fresh piece of paper & cross and align it visually and then move it the # of clicks with the arrow keys you found above. It should land dead on.

Mine is 2 clicks in one direction & 1 click in the other. Works every time.

But, it may stop working sometime because they tune something and you’ll be off a hair - just redo the process to get your new adjustment click values. Mine used to be 5x2 clicks then it misaligned one day and I found it was now 2x1 instead. They did something in the cloud and made it better. Haven’t had it change any more in months.


#5

I’m doing a similar thing to this, but for wedding invitations. I print them on an inkjet printer and then cut them on the Glowforge.

I use a jig the way @bbum describes. Since my sheets are 8.5"x11", my design contains a rectangle around the edge of the paper which is a different color than the design I’m cutting. I cut that out of my jig material while ignoring the rest of the design; place the printed design in the rectangle; ignore the rectangle and cut the design into the invitation.

The key to this is to pretend that I can’t see the printbed at all since looking at the image just confuses the issue.

Though, I’ve got a little more slop in my design than you do because the cut and printed elements aren’t as close together. But it can’t be too far off or it would look lopsided.


#6

Note that the software de-warps the wide angle image and that de-warping algorithm is the source of the inaccuracy (and is being refined over time).

The material height is absolutely critical to making the image as accurate as possible. Even if you have something labeled “3mm” thick, measure it with a set of calipers! The lovely folks at the wood industry decided long ago that wood dimensions would be labeled an entirely different value than what they actually are (go measure a 2x4 sometime. Then cry.).


#7

Please read the following tutorial:

The problem with what you are trying to do is that there is actually no relationship created in the software between something that gets printed out on an Inkjet printer and the cutting lines. (We used to call them Print and Cut files. The laser is designed to Engrave and Cut, but you are not engraving the image here.)

There is a way to do it, but it requires some additional steps as @cynd11 outlines in her discussion at the tutorial above. :slightly_smiling_face:


#8

The software on your Glowforge is responsible for ensuring that the print lands on the material in the same place as the preview. When you’re done with a print, let a new image load. If the print appears on screen far from where it was supposed to go, you may have an alignment problem.

Most alignment problems come from the material being closer or farther from the camera than expected. While the software is still improving, you can take these steps for the most accurate alignment results:

  • Use Proofgrade™ materials.
  • If you don’t use Proofgrade materials, use a precision set of calipers to measure your material, and enter the thickness in the “uncertified materials” dialog.
  • Use material that is not warped or tilted.
  • Place your design near the center of the bed.
  • Clean the area underneath your crumb tray, particularly the four indentations on the floor.
  • Reboot the machine. Alignment can drift over time, particularly if you bump the head of your Glowforge while removing material.

Should you finish all of these steps, and find that you have an alignment error of more than 1/4", please contact us so we can investigate.


#9

Thanks everyone for the help. I have now spent many hours on your suggestions. I have used a micrometer to measure the correct depth of material. Most things do not frustrate me but i’m afraid this does. It seems like such a simple thing but i think this maybe isn’t the machine i need to do what i want to do. Shown are the crosshairs at the front right of the laser bed. The first scores were way off, second were closer, and third pretty close. I can see perhaps if I really worked at this I might be able to get them pretty close, but I don’t want to be having to adjust every image on my page and have the possibility that it is slightly off, or the software has changed over night. I am going to be paying for giclee prints so I can’t be messing around like this. Thanks for your help though, I really did appreciate the ideas.


#10

If your scale is changing between inkscape and GF, then double-check all the discussions on getting that right – artboard size, not working in pixels, etc. You should be able to do something like this with a few test cuts and a jig, and never have to worry about optical positioning.


#11

That’s what I would like! Okay, I’ll do some more reading… Thanks for providing hope :slight_smile:


#12

I’m going to close this topic. If you continue to have trouble or think of another question, please post a new topic. I’m happy to help!


#13